MarcoBuster/Magisk
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Fail fast when possible

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This commit is contained in:
topjohnwu 2018-06-13 18:14:23 +08:00
parent b2f719989d
commit 08e98eeb15
1 changed files with 16 additions and 8 deletions
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24
su_daemon.c
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@ -174,13 +174,13 @@ static struct su_info *get_su_info(unsigned uid) {
break; break;
case ROOT_ACCESS_ADB_ONLY: case ROOT_ACCESS_ADB_ONLY:
if (info->uid != UID_SHELL) { if (info->uid != UID_SHELL) {
LOGE("Root access is disabled for ADB!\n"); LOGE("Root access limited to ADB only!\n");
info->access = NO_SU_ACCESS; info->access = NO_SU_ACCESS;
} }
break; break;
case ROOT_ACCESS_APPS_ONLY: case ROOT_ACCESS_APPS_ONLY:
if (info->uid == UID_SHELL) { if (info->uid == UID_SHELL) {
LOGE("Root access limited to ADB only!\n"); LOGE("Root access is disabled for ADB!\n");
info->access = NO_SU_ACCESS; info->access = NO_SU_ACCESS;
} }
break; break;
@ -221,6 +221,13 @@ void su_daemon_receiver(int client, struct ucred *credential) {
.pipefd = { -1, -1 } .pipefd = { -1, -1 }
}; };
// Fail fast
if (ctx.info->access.policy == DENY && !ctx.info->access.log && !ctx.info->access.notify) {
UNLOCK_UID();
write_int(client, DENY);
return;
}
// If still not determined, open a pipe and wait for results // If still not determined, open a pipe and wait for results
if (ctx.info->access.policy == QUERY) if (ctx.info->access.policy == QUERY)
xpipe2(ctx.pipefd, O_CLOEXEC); xpipe2(ctx.pipefd, O_CLOEXEC);
@ -230,10 +237,7 @@ void su_daemon_receiver(int client, struct ucred *credential) {
* The parent process will wait for the result and * The parent process will wait for the result and
* send the return code back to our client * send the return code back to our client
*/ */
int child = fork(); int child = xfork();
if (child < 0)
PLOGE("fork");
if (child) { if (child) {
// Wait for results // Wait for results
if (ctx.pipefd[0] >= 0) { if (ctx.pipefd[0] >= 0) {
@ -284,7 +288,7 @@ void su_daemon_receiver(int client, struct ucred *credential) {
UNLOCK_UID(); UNLOCK_UID();
// ack // ack
write_int(client, 1); write_int(client, 0);
// Become session leader // Become session leader
xsetsid(); xsetsid();
@ -445,7 +449,11 @@ int su_client_main(int argc, char *argv[]) {
} }
// Wait for acknowledgement from daemon // Wait for acknowledgement from daemon
read_int(socketfd); if (read_int(socketfd)) {
// Fast fail
fprintf(stderr, "%s\n", strerror(EACCES));
return DENY;
}
if (atty & ATTY_IN) { if (atty & ATTY_IN) {
setup_sighandlers(sighandler); setup_sighandlers(sighandler);